cool的比較級是cooler。

cool 英[kuːl] 美[kuːl]

adj.涼爽的; 冷靜的; 涼的; 涼快的; 使人感到涼爽的; 冷色的; 鎮靜的; 平靜的;

n. 涼爽；涼爽的空氣

v. (使)變涼，冷卻; 冷靜下來; 鎮靜下來; 冷淡下來;

The house was refreshingly cool inside.

屋內清涼宜人。

The city"s population prepared to flee heat for the relative cool of the rivers.

該市居民準備逃到天氣較為涼爽的江河流域避暑。

We dived into the river to cool off.

我們一頭跳進河裡，涼快一下。

Cooler weather is forecast for the weekend.

預報本週末天氣較涼。